The invention relates to a method of manufacturing a device, preferably a semiconductor device, whereby a mask having an opening extending down to a bare body is provided on a surface of the body, after which a substance is implanted into the body through said opening, after which the mask is removed.
Such a method is particularly suitable for manufacturing semiconductor devices which, as transistors, are provided with buried conductor, semiconductor, or insulating layers. The substance then comprises, for example, Co, Ni, Ir, Fe, C, Y or O. Alternatively, for example, optoelectronic devices having optically active layers may be made by the method through the local implantation of ions of a rare earth metal into, for example, a glass body. The mask may comprise photoresist, silicon oxide, or, for example, a metal such as tungsten. The opening in the mask is made so as to reach down to the body, i.e. the body is bare in the opening, so that intermixing of any layer possibly present in the opening with the body during implantation is avoided.
A method of the kind mentioned in the opening paragraph is known from "Formation of Buried CoSi.sub.2 by Ion Implantation" by K. Kohlhof et al. in Applied Surface Science 38 (1989), p. 207, whereby a silicon oxide mask is provided on a silicon semiconductor body. The opening is manufactured by lithographic techniques, whereby the silicon oxide is locally completely removed. A high dose of Co (approximately 3 10.sup.17 ions.cm.sup.-2) is implanted into the semiconductor body at an energy of 200 keV through the opening. The mask screens the surface of the semiconductor body outside the opening against implantation by Co. The semiconductor body is kept at a temperature of 350.degree. C. during implantation in order to repair part of the damage caused by the implantation. The implanted Co is convened into CoSi.sub.2, which can function as a buried conductor layer, after heat treatments at approximately 700.degree. C. and 1,000.degree. C.
The known method described has the disadvantage that the semiconductor body below the opening is not only implanted with the substance Co, but that the semiconductor body is also polluted, so that electrical and chemical properties of the semiconductor body change. For example, when the silicon oxide of the mask is removed by etching, the semiconductor body is also affected by the etching in the opening.